Atari 1040 STe Drive Swap Mod Problem

[oguzog]

My 1040STe has some modifications;

Quadtos (1.06-.1.62-2.06-SuperTOS)
And
boot floopy selector (by wiring 2 of yamaha chip pins)

I did that because wanted to boot from my gotek (which has HxC fw)

now i don't need to boot from gotek anymore.

All i want is copy from st to real disk.

but i tried every combination but no way my ste see the contents of a and b drive same time. so i cannot copy disks. What do i do wrong?

Whatever i do, I cannot access both drives. Only one works.

My friend made this mod.

Let's see if my mod is faulty.

Pin 19 Chip --> Red --> SW 3
Pin 20 Chip --> Green --> SW 6
Pin 19 MB --> White --> SW 2
Pin 20 MB --> White --> SW 5

Switch numbering (Solder Side)
1-2-3
4-5-6

There is also 2 blue wires soldered;

Blue Wire 1 --> SW 1 to SW 6
Blue Wire 2 --> SW 4 to SW 3

Conclusion;

SW Left (External Boot)
1(which connected to 6) to 2 --> 19 MB to 20 Chip
4(Which connected to 3) to 5 --> 20 MB to 19 Chip

SW Right (Internal Boot)
2-3 --> 19 MB to 19 Chip
5-6 --> 20 MB to 20 Chip

 

 

[ParanoidLittleMan]

Possible that YM chip is damaged and only 1 of that 2 outputs work.  Should check it with voltmeter while selecting drive A, then B .

[oguzog]

1 hour ago, ParanoidLittleMan said:

Possible that YM chip is damaged and only 1 of that 2 outputs work.  Should check it with voltmeter while selecting drive A, then B .

If i boot from Gotek. I can.

If i boot from Internal. I can.

 

Problem is i cannot access both same time.

[ParanoidLittleMan]

Well, looking it literally, not possible to access both same time. You mean not possible to perform copy from A to B, or versus.

But, when you boot from Gotek YM drive A select output is active. When you boot from Internal, where switch is in opposite position, it is still same YM pin active. So, it is that drive B select YM output pin is possibly damaged.

Normal way of work is that boot is from A. And it changes not if you move switch in opposite position. TOS will still activate same pin of YM chip.

Possible to set system variable to force boot from B. But it will not solve your problem.

[oguzog]

20 hours ago, ParanoidLittleMan said:

Well, looking it literally, not possible to access both same time. You mean not possible to perform copy from A to B, or versus.

But, when you boot from Gotek YM drive A select output is active. When you boot from Internal, where switch is in opposite position, it is still same YM pin active. So, it is that drive B select YM output pin is possibly damaged.

Normal way of work is that boot is from A. And it changes not if you move switch in opposite position. TOS will still activate same pin of YM chip.

Possible to set system variable to force boot from B. But it will not solve your problem.

If i boot from gotek i can boot from gotek.

And if boot from internal i can boot from internal no problems.

 

But never access both drives same time.

[ParanoidLittleMan]

Repeating self will not make this progress.

[oguzog]

On 8/27/2020 at 11:53 AM, ParanoidLittleMan said:

Possible that YM chip is damaged and only 1 of that 2 outputs work.  Should check it with voltmeter while selecting drive A, then B .

If you tell me how to check pins i can do that. I am not experienced.

[ParanoidLittleMan]

Easiest is to connect voltmeter at switch - to red and green wires, which lead to YM pins 19 and 20.

Lines are low active, so there should be roughly around 4 V when no drive active. When is active (light on drive on) it is near 0 V.

You may need someone to help - who will just click on drive A: , then B: to activate. Then line 19 or 20 must go down for couple seconds, while it reads floppy.

For me, this looks like pin what selects drive B is broken - so will not go low. In that case need to replace YM chip.

Just to add that those lines of YM are very low power (current), easy to overload.

[oguzog]

Will try to get help from wife and she has twins 5 months I will try my chance.

 

But meanwhile, I will measure my cable now. I will list which pin goes to where. This will be a good start. Because my friend maybe did something wrong in cable.

[oguzog]

Progress;

I think i have faulty connection in my cable;

On the left my cable. on the right correct diagram ( i suppose)

So first i will desolder FD14 to DIN5.
then desolder FD10 to DIN8 and solder to DIN5.

Will this be enough?

Also this correct guide states all the odd pins must be connected to 3 and 7.

Is that mandatory? if i leave like this (Only 13 and 27 connected to 3 and 7) will i be in trouble again?

[oguzog]

I've corrected my cabling and it works great!

Thanks for your comments